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Interconnection Intents
draft-contreras-nmrg-interconnection-intents-03

Document Type Active Internet-Draft (individual)
Authors Luis M. Contreras , Paolo Lucente
Last updated 2022-10-24
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draft-contreras-nmrg-interconnection-intents-03
NMRG                                                       LM. Contreras
Internet-Draft                                                Telefonica
Intended status: Informational                                P. Lucente
Expires: 27 April 2023                                               NTT
                                                            October 2022

                        Interconnection Intents
            draft-contreras-nmrg-interconnection-intents-03

Abstract

   This memo introduces the use case of the usage of intents for
   expressing advance interconnection features, further than traditional
   IP peering.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on 4 April 2023.

Copyright Notice

   Copyright (c) 2022 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   Please review these documents carefully, as they describe your rights
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   provided without warranty as described in the Revised BSD License.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Evolution of Network interconnection  . . . . . . . . . . . .   3
     2.1.  Potential interconnection intent types  . . . . . . . . .   3
     2.2.  Interconnection intent lifecycle  . . . . . . . . . . . .   4
     2.3.  Protocol aspects  . . . . . . . . . . . . . . . . . . . .   5
   3.  Interconnection intent structure  . . . . . . . . . . . . . .   5
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   The success of Internet-based services has been built on top of the
   global reachability of content accessed by the end-users, which is
   facilitated by the interconnection of individual networks owned by
   distinct service providers constituting independent administrative
   domains.

   Such interconnection services have been initially based simply on
   delivery of IP traffic between the interconnected parties leveraging
   on BGP.  This peer model enables full connectivity.  However, the
   traditional interconnection model shows some limitations when
   additional information to that related to routing is needed.

   New network capabilities based on programmability and virtualization
   are producing service situations where a connectivity-only approach
   is not sufficient.  The increasing availability of computing
   capabilities internal to the networks, or attached to them, enable
   new scenarios where those capabilities can be consumed through the
   advertisement or exposure of these execution environments (i.e., in
   terms of compute, storage and associated networking resources).  Such
   information from an interconnected provider can be obtained from e.g.
   [I-D.llc-teas-dc-aware-topo-model].

   In addition or complementary to that, even services or network
   functions could be advertised in order to make them available for
   interconnection.  For example, as service we could consider the
   advertisement of CDN capabilities as in CDNi approach [RFC7336],
   while as network function we could consider functions like firewall,
   CGNAT, etc, present in the network
   [I-D.ietf-teas-sf-aware-topo-model].

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   All these scenarios present clear evolutions of the interconnection
   model which can not be simply expressed through existing mechanisms,
   or at least, cannot be expressed in a simple (and comprehensive) way
   with such existing mechanisms.  Here is where an advanced
   interconnection intent can assist on declaring the goal of the
   interconnection transcending pure IP traffic exchange and including
   more advance capabilities as the ones mentioned before.

2.  Evolution of Network interconnection

   It becomes clear the trend to increasingly rely on multi-domain
   scenarios for the provision of services.  For instance, the access
   today to an on-demand OTT video on Internet implies the interaction
   of more than one single administrative domain.  Thus, end-to-end
   service delivery over multiple providers or domains is becoming the
   norm.

   Complex network services leveraging on virtualization solutions and
   different infrastructure environments pertaining to distinct
   administrative domains (i.e., operated and managed by distinct
   providers) can be easily foreseen.

   It is then necessary to explore mechanisms for interconnecting that
   multiple domain environments in a common, portable way independently
   of the owner of such infrastructure.

2.1.  Potential interconnection intent types

   The interconnection intent should provide enough abstractions to
   express a variety of interconnection options.

   The purpose of the interconnection intent can be multiple:

   *  To enable multi-domain network service programming, by soliciting
      interconnection of service / network functions in different
      domains

   *  To enable multi-domain deployment of virtualized network
      functions, by advertising the availability of compute and storage
      resources in different domains

   *  To facilitate multi-domain network function or service charging,
      by advertising (cumulative) costs in the different domains

   *  To enable traffic interchange, ie.  IP as in traditional peering
      or optical

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   *  To put in place the right collection of policies to implement and
      operate the interconnection

   *  To facilitate whatever combination of all of them

2.2.  Interconnection intent lifecycle

   [RFC9315] defines an intent lifecycle composed of two phases, namely
   fulfillment and assurance.  Figure 1 captures the intent procedure
   for the fulfillment phase.

          User Space   :       Translation / IBS       :  Network Ops
                       :            Space              :     Space
                       :                               :
         +----------+  :  +----------+   +-----------+ : +-----------+
 Fulfill |recognize/|---> |translate/|-->|  learn/   |-->| configure/|
         |generate  |     |          |   |  plan/    |   | provision |
         |intent    |<--- |  refine  |   |  render   | : |           |
         +----------+  :  +----------+   +-----------+ : +-----------+
                       :                               :
 .........................................................................

       Provider A      :                   Provider B
       ----------      :                   ----------
                       :
  - Select interconn.  : - Mapping of intent types to  : - Establishment of
    intent type        :   protocols / APIs for        :   protocol sessions
  - Specify targeted   :   coveying targeted resources :   or API requests
    resources (i.e.,   : - Parametrization of that     :   for configure or
    routes, compute    :   protocols / APIs, e.g.      :   provisioning
    quotes, service    :   leveraging on data models   :   targeted resources
    functions, etc.)   :                               :
                       :                               :

      Figure 1: Fulfillment phase of the Interconnection Intent

   Similarly, Figure 2 sketches the intent procedure for the assurance
   phase.

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                         :                  +--------+   :
                         :                  |validate|   :  +----------+
                         :                  +----^---+ <----| monitor/ |
   Assure   +-------+    :  +---------+    +-----+---+   :  | observe/ |
            |report | <---- |abstract |<---| analyze | <----|          |
            +-------+    :  +---------+    |aggregate|   :  +----------+
                         :                 +---------+   :
   .....................................................................

         Provider A      :                   Provider B
         ----------      :                   ----------
                         :
    - Analysis of the    : - Checking of monitored data  : - Collection of
      reported metrics   :   for internal closed loops   :   telemetry info
      against the intent :   to ensure commited SLOs     :   related to allocated
      request            :   (inner closed loop)         :   resources (i.e.,
    - Trigger of actions : - Aggregation of data         :   routes, compute
      if needed, e.g.,   :   producing an abstracted view:   quotes, service
      new intent (outer  :   fitted to the intent request:   functions, etc.)
      closed loop)       :                               :

       Figure 2: Assurance phase of the Interconnection Intent

   Both Fulfillment and Assurance phases are integral part of the
   interconnection intent.

2.3.  Protocol aspects

   Ultimately the ideas and notions elaborated in this document will
   need to find room in a framework made of one or multiple protocols
   (ie.  BGP, LISP, ALTO, etc.) and/or API definitions.  While the exact
   definition of such framework is left as future work, in this document
   we intend to perform some seminal work in this sense (ie. identify
   existing protocols that could fit, determine gaps of such protocols,
   etc.).

3.  Interconnection intent structure

   In order to address the different interconnection intent types
   described in section 2.1, the structure of the intent should be
   sufficiently flexible to allow the expression of different targets.
   Thus, the intent structure could include:

   *  Information of the type of data traffic being subject of the
      interconnection intent (e.g., IP prefixes involved) among
      providers.

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   *  Service functions expected to be supported by the peer provider.
      These could be expressed in terms of type of service function and
      number of instances required.  Furthermore, it can be necessary to
      consider how the service functions are expected to be connected in
      terms of topology (i.e., service function graph).

   *  Resources expected to be offered by the peer provider.  These
      could be expressed in terms of raw values of number of CPUs,
      memory and storage size, or bandwidth capacity, or alternatively,
      in terms of quotas grouping resources in a predefined manner.

   *  Constraints that could apply to whatever of the elements included
      in the interconnection intent, including traffic steering ones.
      Aspects such as committed rates, burst size, cumulative traffic,
      service function affinity, redundancy, traffic engineering (e.g.,
      latency), etc., could be part of such constraints.

   *  Further information that could be necessary for delivering an end-
      to-end service by means of the intent.

4.  Security Considerations

   To be done.

5.  IANA Considerations

   This draft does not include any IANA considerations

6.  References

   [I-D.ietf-teas-sf-aware-topo-model]
              Bryskin, I., Liu, X., Lee, Y., Guichard, J., Contreras, L.
              M., Ceccarelli, D., Tantsura, J., and D. Shytyi, "SF Aware
              TE Topology YANG Model", Work in Progress, Internet-Draft,
              draft-ietf-teas-sf-aware-topo-model-09, 27 February 2022,
              <https://www.ietf.org/archive/id/draft-ietf-teas-sf-aware-
              topo-model-09.txt>.

   [I-D.llc-teas-dc-aware-topo-model]
              Lee, Y., Liu, X., and M. Luis Contreras, "DC aware TE
              topology model", Work in Progress, Internet-Draft, draft-
              llc-teas-dc-aware-topo-model-02, 11 July 2022,
              <https://www.ietf.org/archive/id/draft-llc-teas-dc-aware-
              topo-model-02.txt>.

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   [RFC7336]  Peterson, L., Davie, B., and R. van Brandenburg, Ed.,
              "Framework for Content Distribution Network
              Interconnection (CDNI)", RFC 7336, DOI 10.17487/RFC7336,
              August 2014, <https://www.rfc-editor.org/info/rfc7336>.

   [RFC9315]  Clemm, A., Ciavaglia, L., Granville, L. Z., and J.
              Tantsura, "Intent-Based Networking - Concepts and
              Definitions", RFC 9315, DOI 10.17487/RFC9315, October
              2022, <https://www.rfc-editor.org/info/rfc9315>.

Acknowledgments

   This work has been partly funded by the European Commission through
   the H2020 project 5GROWTH (Grant Agreement no. 856709).

Authors' Addresses

   Luis M. Contreras
   Telefonica
   Ronda de la Comunicacion, s/n
   Sur-3 building, 1st floor
   28050 Madrid
   Spain
   Email: luismiguel.contrerasmurillo@telefonica.com
   URI:   http://lmcontreras.com/

   Paolo Lucente
   NTT
   Siriusdreef 70-72
   2132 Hoofddorp, WT
   Netherlands
   Email: paolo@ntt.net

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